Hello Mikey
I don't know the definitive answer, and I suspect Bailey will consider that type of information to be commercially sensitive so don't hold your breath.
However having looked at the construction, I guess that the construction and preparation of the new aluminium panels may take longer at the sub assembly stage, but be much faster to assemble on the production line. So it will be swings and round-a-bouts.
On balance though I sure bailey will have been looking for overall savings or a significantly lower life cost for the product. e.g. lower warranty costs.
I sincerely hope that Bailey have come up with better construction method. Where the Pegasus leads I am fairly confident that other models will adopt the same construction when they come up for renewal.
Other manufacturers will try to produce their own solutions, or may be Bailey will licence the process to other manufacturers.